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THE EFFECTS OF THROUGH SPACE 2P-3D OVERLAP IN THE WITTIG REACTION
Abstract
In a study of the mechanism of a lithium ion mediated Wittig reaction, the influence of "through space" electron donating substituents on phosphorus upon the stereoselectivity of a carefully selected Wittig olefination reaction was examined. The model system was chosen such that the influence of the "through space effect" could be evaluated prior to, and subsequent to, oxaphosphetane formation. Two conclusions could be reached: (a) With THF as solvent and lithium ion present, the decomposition of cis-oxaphosphetane (A) into cis-stilbene and phosphine oxide is not affected by the presence of groups able to participate in a 2p-3d overlap; and (b) In the Wittig condensation of ylide (B) with benzaldehyde (THF/BuLi), cis-stilbene stereoselectivity is observed. A mechanism is proposed for each of the above mentioned lithium ion mediated reactions. A preliminary survey of the feasibility of the condensation of the anions derived from open chain Reissert analogues with vinyltriphenylphosphonium bromide for the synthesis of heterocyclic systems is also reported.
Subject Area
Chemistry
Recommended Citation
BEAVER, BRUCE DAVID, "THE EFFECTS OF THROUGH SPACE 2P-3D OVERLAP IN THE WITTIG REACTION" (1984). Doctoral Dissertations Available from Proquest. AAI8500056.
https://scholarworks.umass.edu/dissertations/AAI8500056